Alert archive / Maine / Mesoscale Discussions in 2016

Mesoscale Discussion 19

January 13, 2016Aroostook County, Penobscot County, Piscataquis County, Maine

The Storm Prediction Center issued this mesoscale discussion at Jan 13, 2016, 4:16 AM EST for Aroostook County, Penobscot County, Piscataquis County, Maine. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 13, 2016, 4:16 AM EST (09:16 UTC)
Expired: Jan 13, 2016, 9:15 AM EST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Aroostook County, ME, Penobscot County, ME, Piscataquis County, ME

The radar

The Caribou radar (KCBW), 71 km from the middle of the area, began a volume at 09:20 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Caribou, ME (KCAR), launched 00:00Z, 9.3 hours before the alert went out and 93 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1384 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 346 m²/s²
0-3 km storm-relative helicity: 466 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

342 
ACUS11 KWNS 130916
SWOMCD
SPC MCD 130916 
MEZ000-131415-

MESOSCALE DISCUSSION 0019
NWS STORM PREDICTION CENTER NORMAN OK
0316 AM CST WED JAN 13 2016

AREAS AFFECTED...NORTHERN AND EASTERN MAINE

CONCERNING...HEAVY SNOW 

VALID 130916Z - 131415Z

SUMMARY...HEAVY SNOWFALL RATES 1-3 INCHES PER HOUR WILL DEVELOP
THROUGH 12-14Z ACROSS CENTRAL...EASTERN INTO NORTHERN MAINE.  THESE
RATES WILL THEN GRADUALLY DIMINISH FROM SOUTH TO NORTH DURING
MID-LATE MORNING.

DISCUSSION...PORTIONS OF CENTRAL INTO EASTERN AND NORTHERN MAINE ARE
EXPECTED TO HAVE A 3-4-HOUR PERIOD OF HEAVY SNOWFALL RATES BETWEEN
09-13Z AS UPWARD VERTICAL MOTION DRAMATICALLY INCREASES AS A RESULT
OF A DEEPENING SHORTWAVE TROUGH AND ATTENDANT SURFACE LOW INTO THIS
MORNING.  SINCE AROUND 07Z...MOSAIC RADAR IMAGERY INDICATED 
PRECIPITATION INCREASING IN AREAL COVERAGE ACROSS MUCH OF THE
EASTERN HALF OF MAINE.  09Z SURFACE ANALYSIS SHOWED AN AREA OF LOW
PRESSURE DEEPENING NEAR THE COAST OF DOWNEAST MAINE /992 MB/ WITH
2-HR PRESSURE FALLS OF 3-5 MB FROM SOUTHEAST MAINE INTO NEW
BRUNSWICK/NOVA SCOTIA.  THESE PRESSURE FALLS INDICATE THE LOW-LEVEL
WAA UNDERWAY ACROSS THIS REGION IN RESPONSE TO A DEEPENING SHORTWAVE
TROUGH APPROACHING FROM SOUTHERN NEW ENGLAND.  THIS TROUGH IS
EXPECTED TO SLOW ITS EASTWARD PROGRESS SOME INTO THIS MORNING AS IT
UNDERGOES FURTHER DEEPENING AND TAKES ON A MORE NEGATIVE TILT ACROSS
MAINE...NOVA SCOTIA AND NEW BRUNSWICK.  

RUN-TO-RUN RAP FORECAST SOUNDINGS REMAIN CONSISTENT...INDICATING
STRONG UPWARD VERTICAL MOTION OCCURRING FOR 3-4 HOURS WITHIN THE
DENDRITIC GROWTH ZONE /-12 TO -17 C/ ACROSS THE DISCUSSION AREA. 
THIS COMBINED WITH RAP/NAM/GFS SNOW-TO-LIQUID RATIO GUIDANCE ALL
SUGGEST AN INCREASE IN SNOWFALL RATES /1-3 INCHES PER HOUR/ CAN BE
EXPECTED THROUGH 12-14Z.

..PETERS.. 01/13/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...CAR...GYX...

LAT...LON   47216868 47006795 45566762 45046767 44746846 45536952
            46307008 47096962 47216868

Nearby

Mesoscale Discussions in Maine, 2016 Every mesoscale discussion in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.